Hooked on Secrecy: Why Tuna’s Black Box Puts Oceans and Investors at Risk
- Industry News
- Jun 17
- 6 min read
For decades, tuna has been synonymous with convenience and protein-rich plates. But behind the tins, sashimi trays, and supermarket promotions lies an industry shrouded in opacity and fraught with ecological and financial risk. Now, a new report from Planet Tracker, Tuna Turner: Investors Must Turn Up Transparency in the Tuna Industry, reveals just how little we know about who is catching the world’s tuna, where it’s being fished, and at what environmental cost—and why that’s a ticking time bomb for investors and the planet alike.
This isn’t just about ocean health. It’s about fiduciary responsibility, risk exposure, and a systemic data failure that leaves financial institutions and food companies blind to their own supply chains.
Transparency Is Good Business—But It's Lacking at Sea
The global tuna industry is worth billions and supplies a key share of global seafood consumption. Yet Planet Tracker’s analysis found that over 60% of tuna catch is effectively “dark”—untraceable to any identifiable company or vessel using public data. Even among the world’s top thirty tuna-harvesting companies (dubbed the “Tuna 30”), more than half of the catch volumes could not be tied to an AIS-tracked (satellite-monitored) vessel.
This level of opacity presents a fundamental challenge for sustainability-conscious investors. Without verifiable data on what is caught, where, how, and by whom, due diligence is impossible. The risk is not just theoretical. Companies operating in regulatory blind spots may be exposed to reputational damage, non-compliance fines, or exclusion from ESG-aligned portfolios. Those who stay silent may be penalized not just by activists—but by markets.
According to Planet Tracker’s modeling, improving transparency through satellite tracking and disclosure could increase a tuna company’s valuation by 1% and profitability by 0.6% over five years, thanks to enhanced reputational value, better market access, and reduced legal risk. In an industry where margins are tightening and sustainability scrutiny is growing, that’s no small gain.
“There’s no excuse anymore. The technology exists. The data is there. The only missing ingredient is corporate will,” said Francois Mosnier, Head of the Ocean Programme at Planet Tracker and lead author of the report.
An Ecological Keystone in Decline
Tuna are more than commodities. They are keystone predators that drive nutrient cycling in marine ecosystems. Their movement fertilizes phytoplankton, which generate half of the planet’s oxygen and absorb massive quantities of carbon dioxide. Yet most tuna species are in sharp decline. Biomass for key commercial species has dropped by 40–80%, and several—including bigeye, Pacific bluefin, and Southern bluefin tuna—are listed as vulnerable or endangered by the IUCN.
Industrial overfishing, exacerbated by the use of fish aggregating devices (FADs) and bycatch-heavy techniques like longlining, is largely to blame. FADs alone have littered the ocean with more than 1.4 million plastic buoys between 2007 and 2021, drifting across 134 million square kilometers—over a third of Earth’s ocean surface. Many end up abandoned, contributing to marine pollution and ghost fishing.
And it’s not just tuna that suffer. Sharks, turtles, seabirds, and juvenile tuna are routinely caught in industrial gear. One study in the Pacific Ocean found longline fleets alone caught nearly 1.8 million sharks in a single year. Purse seine nets, which surround schools of tuna near FADs, also pull in large quantities of non-target species. These practices degrade biodiversity and threaten the stability of marine ecosystems.
The Tuna 30: Big Players, Bigger Blind Spots
Planet Tracker’s report names names. The Tuna 30—companies based predominantly in Spain, South Korea, China, and Japan—collectively harvest 46% of the world’s tuna catch. Yet only four of them publicly report any catch data, and only one—Italy’s Bolton Group—comprehensively discloses by species, region, gear type, and sustainability certification.
Maruha Nichiro, Dongwon Industries, and Albacora are among the largest harvesters of tuna from “at-risk” stocks—those not rated green by the International Seafood Sustainability Foundation (ISSF) for both abundance and fishing mortality. Several are also key harvesters of threatened species like bigeye and Pacific bluefin. But without robust public disclosure, their precise impact remains opaque.
For investors, this is not just an environmental issue—it’s a red flag. When nearly every major harvester of a global commodity fails to disclose basic operational data, it becomes impossible to distinguish leaders from laggards, or to model risk accurately.
Dark Tuna and AIS Gaps: What We Can’t See Can Hurt
To estimate catch volumes, Planet Tracker used satellite AIS data to track vessel behavior. They matched fishing events with species distribution models and vessel ownership information to reconstruct who’s catching what and where. This methodology led to an unsettling finding: over 56% of catch volumes from the Tuna 30 are not linked to any AIS-tracked vessel.
Some vessels may turn off AIS to avoid piracy or protect commercial secrets, but Planet Tracker also identified over 5,400 intentional AIS gaps—instances where tracking was likely disabled. In several cases, companies spent more time fishing with AIS off than on. Spanish firm Jealsa Rianxeira and Japan’s Kyokuyo Co, for instance, had AIS-off-to-on fishing ratios of 17:1 and 60:1, respectively.
While AIS is not universally required—and VMS (Vessel Monitoring Systems) data is often confidential—this level of invisibility undermines traceability, weakens accountability, and leaves room for illegal, unreported, and unregulated (IUU) fishing to persist under the radar.
External Sourcing Isn’t a Free Pass
Major brands like Thai Union, Bolton, and Mitsubishi may not catch much tuna directly, but they source massive volumes from external fleets. Thai Union, for example, sources 97% of its tuna from other companies. Yet few disclose their supplier lists, and even fewer disclose volumes by supplier or region.
This sourcing opacity presents a dilemma. While these companies often lead in sustainability pledges, their ability to enforce standards depends entirely on traceability. Without disclosing the origin of tuna, even the most polished ESG report becomes a hollow promise.
The report suggests that at a minimum, companies relying on third-party suppliers should publish their supply lists and push for AIS adoption across their sourcing networks. Without this, even well-intentioned buyers risk inadvertently supporting unsustainable or illegal operations.
Investment Risks Are Mounting
The report’s financial modeling shows that enhancing AIS use and catch disclosure yields a modest but measurable financial upside. This includes potential premium pricing, preferred supplier status, lower insurance and borrowing costs, and improved brand trust. The only significant downside—a possible 2% drop in catch volume due to competition spying on AIS data—is more than offset by the benefits.
In a world where ESG data is increasingly scrutinized, failing to disclose is no longer a neutral act—it becomes a liability. As Mosnier notes, “If you can’t measure it, you can’t manage it. And if you can’t manage it, investors should ask: what else don’t we know?”
A Blueprint for Action
The report lays out a simple, actionable framework: every tuna company—especially the largest—should disclose four core metrics:
What they catch (species)
Where they catch it (region or stock)
How they catch it (gear type)
How much they catch (volume in tonnes)
Where possible, this should be backed by verifiable AIS data and extended to include what proportion is certified by credible schemes like the MSC or enrolled in a Fishery Improvement Project (FIP). For purse seiners, adherence to minimum requirements for responsible FAD use is critical to minimize bycatch and habitat damage.
Transparency isn’t a silver bullet—but it is a starting point. Once basic disclosure is in place, companies and investors can begin to tackle more complex challenges: reducing bycatch, transitioning to lower-impact gear, and ensuring fair labor practices at sea.
Conclusion: Casting Light on a Shadow Industry
The tuna industry sits at the intersection of ocean health, food security, and global finance. Yet it remains one of the least transparent sectors in industrial food production. With its new analysis, Planet Tracker provides a crucial map of who’s fishing, how, and with what impact. The findings are stark—but the solutions are straightforward.
For investors, this is not a niche concern. Tuna is a multi-billion-dollar supply chain that underpins some of the world’s most visible food brands. Ignoring the transparency gap is no longer tenable. It’s time to demand better data, verifiable tracking, and real accountability from the companies pulling tuna from the sea.
Because when it comes to fisheries, what you can’t see can hurt you. And it’s not just about saving the tuna—it’s about saving trust in a global system that feeds billions.
Based on Planet Tracker’s June 2025 report “Tuna Turner: Investors Must Turn Up Transparency in the Tuna Industry.”
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